fs2open.github.com/code/object/objcollide.h

/*
 * Copyright (C) Volition, Inc. 1999.  All rights reserved.
 *
 * All source code herein is the property of Volition, Inc. You may not sell 
 * or otherwise commercially exploit the source or things you created based on the 
 * source.
 *
*/ 



#ifndef _COLLIDESTUFF_H
#define _COLLIDESTUFF_H

#include "globalincs/pstypes.h"
#include <optional>
#include <any>

class object;
struct CFILE;
struct mc_info;

// used for ship:ship and ship:debris and ship:prop
struct collision_info_struct {
	object	*heavy;
	object	*light;
	vec3d	light_collision_cm_pos;	// relative cm collision pos
	vec3d	r_heavy;						// relative to A
	vec3d	r_light;						// relative to B
	vec3d	hit_pos;					// relative hit position in A's rf (r_heavy)
	vec3d	collision_normal;		// normal outward from heavy
	float		hit_time;				// time normalized [0,1] when sphere hits model
	float		impulse;					// damage scales according to impulse
	vec3d	light_rel_vel;			// velocity of light relative to heavy before collison
	bool	collide_rotate;		// if collision is being detected purely from rotation (or submodel movement)
	int		heavy_model_num;			// model of heavy object that is hit
	int		heavy_submodel_num;			// submodel of heavy object that is hit
	bool	edge_hit;				// if edge is hit, need to change collision normal
	bool	submodel_move_hit;		// if collision is against a moving submodel
	bool	is_landing;			//SUSHI: Maybe treat current collision as a landing
	bool 	player_involved;
};

//Collision physics constants
#define COLLISION_FRICTION_FACTOR		0.0f	//Default value if not set in ships.tbl
#define COLLISION_ROTATION_FACTOR		0.2f	//Default value if not set in ships.tbl
#define MIN_LANDING_SOUND_VEL			2.0f
#define LANDING_POS_OFFSET				0.05f

constexpr uint32_t collision_cache_bitshift = 16;

//===============================================================================
// GENERAL COLLISION DETECTION HELPER FUNCTIONS 
// These are in CollideGeneral.cpp and are used by one or more of the collision-
// type specific collision modules.
//===============================================================================

// Keeps track of pairs of objects for collision detection
struct obj_pair	{
	object *a;
	object *b;
	int	next_check_time;	// a timestamp that when elapsed means to check for a collision
};

//Never check again | data for collision post-processing | collision post-proc function
using collision_result = std::tuple<bool, std::any, void (*)(obj_pair *, const std::any& collision_data)>;

extern SCP_vector<int> Collision_sort_list;

#define COLLISION_OF(a,b) (((a)<<8)|(b))

void set_hit_struct_info(collision_info_struct *hit, mc_info *mc, bool submodel_move_hit);

void obj_add_collider(int obj_index);
void obj_remove_collider(int obj_index);
void obj_reset_colliders();
void obj_sort_and_collide(SCP_vector<int>* Collision_list = nullptr);

// Retime all collision pairs, so that all object collisions will be rechecked immediately
void obj_collide_obj_cache_stale(object* objp);

// Returns TRUE if the weapon will never hit the other object.
// If it can it predicts how long until these two objects need
// to be checked and fills the time in in current_pair.
// CODE is locatated in CollideGeneral.cpp
int weapon_will_never_hit( object *weapon, object *other, obj_pair * current_pair );


//	See if two lines intersect by doing recursive subdivision.
//	Bails out if larger distance traveled is less than sum of radii + 1.0f.
// CODE is locatated in CollideGeneral.cpp
int collide_subdivide(vec3d *p0, vec3d *p1, float prad, vec3d *q0, vec3d *q1, float qrad);

void collide_init();

//===============================================================================
// SPECIFIC COLLISION DETECTION FUNCTIONS 
//===============================================================================

// Checks weapon-weapon collisions.  pair->a and pair->b are weapons.
// Returns 1 if all future collisions between these can be ignored
// CODE is locatated in CollideWeaponWeapon.cpp
int collide_weapon_weapon( obj_pair * pair );

// Checks ship-weapon collisions.  pair->a is ship and pair->b is weapon.
// Returns 1 if all future collisions between these can be ignored
// CODE is locatated in CollideShipWeapon.cpp
int collide_ship_weapon( obj_pair * pair );

//Same as above, but for deferred collision processing / usage in multithreading
collision_result collide_ship_weapon_check( obj_pair * pair );

// Checks debris-weapon collisions.  pair->a is debris and pair->b is weapon.
// Returns 1 if all future collisions between these can be ignored
// CODE is locatated in CollideDebrisWeapon.cpp
int collide_debris_weapon( obj_pair * pair );

// Checks debris-ship collisions.  pair->a is debris and pair->b is ship.
// Returns 1 if all future collisions between these can be ignored
// CODE is locatated in CollideDebrisShip.cpp
int collide_debris_ship( obj_pair * pair );

// Checks debris-prop collisions.  pair->a is debris and pair->b is prop.
// Returns 1 if all future collisions between these can be ignored
// CODE is locatated in CollideDebrisShip.cpp
int collide_debris_prop(obj_pair* pair);

int collide_asteroid_prop(obj_pair* pair);
int collide_asteroid_ship(obj_pair *pair);
int collide_asteroid_weapon(obj_pair *pair);

// Checks ship-ship collisions.  pair->a and pair->b are ships.
// Returns 1 if all future collisions between these can be ignored
// CODE is locatated in CollideShipShip.cpp
int collide_ship_ship( obj_pair * pair );
//Same as above, but for deferred collision processing / usage in multithreading
collision_result collide_ship_ship_check( obj_pair * pair );

void collide_mp_worker_thread(size_t threadIdx);

// Checks prop-ship collisions.
int collide_prop_ship(obj_pair* pair);

// Checks prop-ship collisions.
int collide_prop_weapon(obj_pair* pair);

//	Predictive functions.
//	Returns true if vector from curpos to goalpos with radius radius will collide with object goalobjp
int pp_collide(vec3d *curpos, vec3d *goalpos, object *goalobjp, float radius);

//	Return true if objp will collide with some large ship if it moves distance distance.
int collide_predict_large_ship(object *objp, float distance);

// function to remove old weapons when no more weapon slots available.
int collide_remove_weapons();

void collide_ship_ship_do_sound(vec3d *world_hit_pos, object *A, object *B, int player_involved);
void collide_ship_ship_sounds_init();

int get_ship_quadrant_from_global(vec3d *global_pos, object *objp);

bool reject_due_collision_groups(object *A, object *B);

void init_collision_info_struct(collision_info_struct *cis);

// goes over weapons applying gravity-relevant flags
// VERY IMPORTANT if gravity was just turned on or off
void collide_apply_gravity_flags_weapons();
#endif